1. Field of the Invention
This invention relates broadly to bearing systems for use in combination with sailcraft gooseneck units. More particularly, it concerns such bearing systems to be employed with gooseneck units that are moveable along sailcraft masts in aft vertical tracks in the masts, in contrast to gooseneck units that are immoveably fixed to the mast.
2. Description of the Prior Art
Gooseneck units are hardware items used on sailcraft, e.g., sailboats, iceboats, etc., to hold the boom of a sail rig onto the mast while permitting the boom to move horizontally aft of the mast as required to bring the sailcraft over from one tack to the other. Such units are of two general types, i.e., those that are moveable vertically along the mast to adjust the height of the foot of the sail relative to the waterline and those that are immoveably fixed so the foot of the sail remains at a fixed height above the waterline. The present invention relates to the former type of gooseneck unit.
The vertically moveable type of gooseneck is frequently employed on high-performance sailcraft, i.e., racing boats, because this provides an additional means for sail control. Thus, a down-haul can be used with the moveable gooseneck unit to stretch the luff of the sail, which, in turn, controls the sail shape to obtain maximum efficiency out of the sail for varying wind conditions.
Several schemes have been developed to permit the gooseneck to move up and down on the supporting mast. One method widely used, particularly on the smaller sailcraft such as racing catamarans, iceboats, racing dinghys, etc. is to employ an mast that has a longitudinal track built into the aft side of the mast in which a slide member of the gooseneck unit is slideably held for up and down movement. Masts of this type are typically made of sections of extruded aluminum or other metal. The present invention is directed to improvements in this type of sail rig.
Typically in the gooseneck units designed with slide members to move in an aft track in the mast as just mentioned, the mast is metal and the slide member is also metal, e.g., a short section of extruded metal channel. The slide member functions as a bearing for the gooseneck unit upon the mast with the result that large lateral forces are exerted between the outer surface of the slide member and the inner surface of the mast track during operation of the sail rig. Hence, there a tendency for the slide member to bind in the mast track to impede the adjustment of the slide member with change in sailing conditions, e.g., angle of sail, wind direction, etc. This is a particular problem for high-performance sailcraft were prompt adjustment of the gooseneck position without binding problems is essential to efficient operation of the sailcraft. The present invention concerns improvements in sailcraft gooseneck units that mitigates this existing problem of the prior known units.